Description of problem:
Somehow during the gdm update to gdm-2.14.1-1.fc5.2 my /etc/gdm/custom.conf got
deleted. Running gdmsetup in that case causes a crash of gdmsetup when trying to
set security login settings.
Workaround copy /etc/gdm/custom.conf.rpmsave to /etc/gdm/custom.conf and
gdmsetup works again.